This application is based on and claims priority to Japanese Patent Application No. 2001-027045, filed Feb. 2, 2001, the entire contents of which are hereby expressly incorporated by reference.
1. Field of the Invention
The present application generally relates to an engine control unit, and more particularly, an engine management system that prevents excessive engine speed for a predetermined period of time after the engine has been started.
2. Description of the Related Art
Personal watercraft, like other applications that use internal combustion engines as power sources, are experiencing considerable public and governmental pressure to improve not only their performance, but also their exhaust emissions levels. For example, due to the emissions generated by two-stroke powered watercraft, certain recreational areas have banned the operation of such watercrafts. These bans have decreased the popularity of personal watercraft, and have caused manufacturers of these types of watercraft to consider fuel injected engines to power their watercraft and/or other means to reduce emissions levels.
Fuel injected engines are known to provide significantly enhanced performance, power output, and emission control as compared to carbureted engines. Watercraft, however, normally do not have a neutral setting where the engine is allowed to operate without driving the propulsion device.
One aspect of the present invention includes the realization that often times the operator of a watercraft opens the throttle when starting the engine, even though the engine does not need the throttle to be opened. For example, certain known fuel injected engines can be programmed to start quickly and reliably without any manipulation of the throttle by the user. Excessive opening of the throttle during commencement can be both harmful to the various engine bearing surfaces due to low initial oil pressure and high oil viscosity. Additionally, an abrupt thrust from the propulsion unit caused by unnecessarily opening the throttle can make docking maneuvers more difficult.
Another aspect of the present invention is directed to a method of controlling engine operation during start-up in a watercraft. The method includes sensing a throttle valve angle, and determining if said throttle valve angle is larger than a predetermined throttle valve angle associated with normal engine start-up.
A further aspect of the invention is directed to a method of controlling operation of a watercraft engine during a predetermined engine speed range. The method includes sensing a throttle valve angle, and determining if the throttle valve angle is larger than a predetermined throttle valve angle associated with the predetermined engine speed range
Yet another aspect of the present invention is directed to a watercraft having a hull and an engine supported by the hull. The watercraft also includes, a fuel delivery system, an ignition system, a throttle valve, and a controller configured to control operation of the fuel delivery and ignition systems. The controller is configured to at least partially disable at least one of the fuel injection system, ignition systems, and starter motor if the throttle valve is open more than a predetermined amount.
Another aspect of the invention is directed to a method of controlling operation of a watercraft engine. The method includes detecting a temperature of the engine, detecting a speed of the engine, and at least partially disabling at least one of the fuel delivery and ignition systems if the engine speed is above a predetermined speed and the temperature is below a predetermined temperature.
Yet another aspect of the invention is directed to a watercraft having a hull and an engine supported by the hull. The watercraft also includes a fuel delivery system, an ignition system, an engine speed sensor, an engine temperature sensor, and a controller configured to control operation of the fuel delivery and ignition systems. The controller is also configured to at least partially disable at least one of the fuel injection and ignition systems if a speed of the engine is higher than a predetermined speed and if a temperature of the engine is below a predetermined temperature.